Sorry for the long post in advance. I've been reading this, and some other threads about what a black belt is, etc., and for better or worse, I gotta weigh in.
I like what Mike said about the test being a challenge, as well as not placing the student in a test without foreknowledge of their skill. In my own schools, I have never allowed a student to sit for a test for which I did not already believe they were ready, either physically, emotionally, or technically. I have always appreciated the test as a "crisis and observation" piece for assessment of character. Technique will come with practice, but character is something each student must search for within their own hearts, finding the strength to choose - through force of will - to press on even after the body has tried to fail; To reach a point of total fatigue, and find a second wind that is mind moving muscle through intent, not conditioning.
By the time I let them test, I've watched my students train and know their technical capability. I know they already possess adequate knowledge of techniques, forms, kata, etc. I still opt to put them through the crucible. Belt, after belt, after belt. At each level, the bar is raised a little higher. I had one student with excellent form, huge ego/attitude problem, and no grit: The test would start to get challenging, he would start to breathe hard and muss his hair, and insist that he just couldn't go on. Never made it past Green, even after 8 years of dilligent training (3-4x/week, 2 hrs+ per pop). Left my school to train with another guy who gave him a BB in the second week of attendence (read: Once the check cleared).
In contrast, I had a lummox of a student, blind in one eye since birth, and suffering with a number of neurological balance and coordination issues that affected the prettiness of his executions; always moved like a bull in a china shop, and finesse was nowhere in his physical vocabulary. He had trained with me for about 6 years with intermittent breaks for school in another state; while in town, he attended all the classes he could, including the black belt classes (yep, he was more then welcome), so he knew all the material he needed to, and more. And he was good at it. For his Green-to-Brown test, one of the first guys I promoted to BB came out of the woodwork to rake this kid over the coals, while the panel looked on. From full strength throws on a thin carpet to assess breakfalls, to weapons retention sparring (here...you hold this baton and try to hit me with it, and don't let me take it away no matter what, or you fail); weapons disarms (I'm gonna start hitting you with this staff. Your job is to take it away from me however you can, and do not stop until you have done so, or you fail); to freestyle (full-contact, bare-knuckle, head and face OK along with knees and elbows to body and extremities; take-downs and throws followed by blows to the grounded opponent expected...mouthpiece [ only got one set of teeth] and no cup [been studying blocks since day one; should be able to use them under fire]). Richard put this kid through the ringer backwards and forwards, until all of us thought it was overkill...it was for a brown belt, for petes sake. The kid absolutely refused to stop, no matter how beaten, bloody and bruised he got (when I say kid, 22 years old, training with me since 16). After about 20 minutes of straight sparring, the wild man kicked Tom in the gut so hard, it sent him easily a dozen feet back accross the room and into a crumpled heap. Tom lost his lunch, cleaned himself up, straightened out his kimono and belt, then turned right around and came back for another. I stopped the test right there and gave the him his black belt; we didn't have one ready for him, so Richard took his weathered and frayed belt off and gave it to Tom with a deep bow of respect, eyes down. Probably the most well-earned promotion I've ever had the honor to be a part of.
That strength of spirit - never to quit, no matter how ugly the odds or brutal the beating - is the rarest and truest of warrior virtues, and - to me - defines the very essence of what seperates the real black belt from the masses of commercialized yudansha. Anybody can rote-memorize a cirriculum, and develop the athletic capabilities necessary to recite the body of knowledge impressively. Hell, cross-training and sports nutrition are at such an all time high as a technology that there isn't really an excuse for an active, committed student to be anything other than in top notch shape (sez the out of shape goo-bear eating Oreo's while playing on the computer). Not jumping high enough, etc.,...don't even schedule them for the test until you know they can. If, as they do, they demonstrate character flaws unbecoming an officer and a gentleman (a black belt), then flunk them as hard and as fast as you can, tell them why with a suggested course of corrective training (study philosophical classics, meditate, whatever), and mentor their progress with an eye towards shaping the type of character you expect them to possess. If they show the strength of heart for that 1 in 100,000, then slap that snippet of cloth around their waist and belly-kick them into the nearest wall!
If the whole class lacks the strength of heart to press on through the crucible, then by all means, flunk the whole class. I don't charge testing fees, and think they're kinda a rip-off. Most senior students have already continued paying their dues for years, and are often put to work doing the slave labor of kids classes, warm-ups, and the like (I can't stand teaching kids classes). The blood stains on their gi should attest to the fees they paid for the right to test for black belt.
It's called a "1 in 100,000" for a demonstrative reason: 100,000 people will sign up for lessons. 10,000 will make it past the first three months. Of that 10,000, 1000 will become "serious" students. Of that 1000, 100 will stick it out to Brown Belt. Of the 100, 10 will strive to prepare for black. And of those 10, only 1 will show the strength of heart to succeed.
To be that One, perservering through time and challenge to arrive at a finishing line intentionally set far out of reach, leads to a black belt one can be proud of. At that point, it is more than an item of clothing to hold up your pants; it is an accomplishment distinguishing a man or woman of mention from the uncivilized hordes of people who quit at the first or second sign of resistance. It is an insignia worn by a trained mensch, indicating that the person wearing it can and will go the extra mile to accomplish what needs to be accomplished, even though it cost them dearly. Belts made from this cloth can not be bought over the internet, attained through a TV screen, or earned in a happy family atmosphere where everybody gets thier promotions just for showing up and demonstrating positive citizenship by giving a good effort.
Does an instructor have the right to flunk a whole class? Sure. And he should strip himself of his own rank for being such a poor judge of readiness as to put that particular collection of candidates up for examination. Clearly, a senior instructor who would place himself and several of his top students in this position has NOT demonstrated the insight or character required to attain his lofty rank, and would best serve his school, system, and students by recusing himself from any leadership positions in the dojo. Hand the mantle to somebody else, dude. You're not worthy.
Climbing off the soapbox,
Dr. Dave